Composite signaling system.



H. B. STONE. COMPOSITE SIGNALING SYSTEM. .APPLIOATION FILED JULY20,1908.

Patented May 18, 1909.

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H. B. STONE. COMPOSITE SIGNALING SYSTEM.

APPLICATION FILED JULY 20,1908.

922,206. v Patented May 18, 1909.

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HENRY B. STONE, OF PROVIDENCE, RHODE ISLAND.

COMPOSITE SIGNALING SYSTEM.

Specification of Letters Patent.

Patented May 18, 1909.

Application filed July 20, 1908. Serial No. 444,324.

grammatic form various arrangements of i used for simultaneoustelegraphic and telephonic communication.

In composite-signaling systems it is customary to connect one or moretele raph branches to the'main line through the interposition ofimpedance coils whereby the rapidly varying telephone currents areprevented from affecting the telegraph apparatus, and to connect thetelephone branch with the line circuit through the interposition ofcondensers whereby the more slowly varying telegraph currents areprevented from afieoting the telephone system.

It has been found however that the effi-- ciency of the telephone systemis greatly diminished by the-necessity of passing the signaling orringing currents through the I condensers which connect the telephonebranch with the line circuit.

It has been proposed to remedy this defect by employing high-frequencyringing currents such as those produced by means of vibratorsbut the useof such high-frequency ringing cur- .rent is objectionable and hasdeveloped a number of difficulties and limitations inpractice.

It is the object of the present invention to provide a compositesignaling system wherem the ordinary low-frequency ringing current maybe employed by impressing the same on the line c rcuit on the'line sideof the aforesaid condensers, if the latter be .retained, and. itcontemplates in one of its aspects the eliminationof the condensers orinductostatic connection of the telephone branch, of the line circuit.

A further object of my invention is to connect the telegraph branch orbranches of a composite system to the line circuit at a point or-pointsthe potential of whichisnot affected by the developmentof the telephonesignaling current so that such current will'notaiiect theztelegraphapparatus.

illherdrawings Whichaccompany and form;

a part of this application represent in dialine circuit.

circuits and apparatus whereby the fore going objects may beaccomplished.

In the drawings, Figure 1 is an explanatory diagram illustrating a Wellknown composite system in common use today. Fig. 2 represents oneembodiment of my invention in which a simple repeating 0011, having itsprimary bridged across the telephone side of the composite set isemployed for associating the telephone branch with the Fig. 3 representsan extension of the principle shown in Fig. 2, in .Which the repeatingcoil has two sets of secondaries each set consisting oi twocoils-connected in series with one side of the line circuit. Fig. 4shows a modification in which the repeat ing coil has two primarywindings connected in series with the telephone branch and the linecircuit. Fig. 5 represents a further modification in which the rimariesof the re eating coil are connected in series with the to ephone andafeinductively related to the line circuit, the condensers on. the dropside having been discarded.

In the fi ures O 0, represent the sides of an all-meta lic linecircuit.

T T, represent the telegraph branches of the composite signaling system,said sets ineluding, respectively, the batteries B B,, the keys K K, andthe relaysR R,. The tolegraph branches are connected to the line circuitat the points 0 0 respectively, and each is earthed at E. The impedancecoils L I}, are

interposed between the telegraph branches and-the line circuit, and theusual shunts in cluding the condensers (l C, and the impedances L L, maybe connected to earth as shown.

It is usual to connect the two pairs of condensers C (Wand C, U, in thetwo sides of the line circuit between the points of connection therewithof the telegraph branch and the telephone branch. Inasmuch as theringing current .must pass through the condensers C 0- and C, C,-, whichare usually condensers of from two to four microfarads capacity, and asa certain portion of said current necessarily passes through the shuntsincluding the coils L- L,, which are coils of relatively low impedance,it will be clear that the arrangement shown in 1 isquite inefiicient fortransmittinglow-frequency ring in currents. The attem t to improve the eciencyofithe system .s own in :Fig. 1 by the use of'relativelyhigh-frequency ringing currents has not proven successful, artly becauseof the disturbances induce .by such currents in neighboring lines, andpartly because ofthe complexity of the a paratus requiredfor theirproduction and t e difficulty experienced in maintaining the same inproper adjustment.

' The simplest form of my invention is shown in Fig. 2, in which as wellas in the remaining figures, the reference characters have the samesignificanceas in Fig. 1. In Fig. 2, I represents the primary winding ofa re-" peating coil, said primary being bridged across the telephonebranch of the composite system between the points 1) p, and, as shown,connected in series with the springjack S ,of a telephone switch-board.I 1,, are the secondaries of said-repeating coil and each is connectedin series with one of the sides of the line circuit 0 0 The ringingcurrent from the telephone branch will be transmitted to line partlythrough the condensers C C C C, but principally by way of the .repeatingcoil which inductively translates the energy of said currents to theline to reinforce that portion of the energy of said currents receivedfrom said condensers. While the efficiency of transmission is greatlyincreased by the arrangement shown in Fig. 2, it has been found thatvariations in poten tial at the points 0 0 due to the development of theringing currents affects the telegraphbranches and also that thetelegraph current is often heard in the telephone instruments.

In Fig. 3 I have shown a systemwhereby the efficiency of transmission ofthe ringing current may be still further improved and atthe same timethe mutual action of the tele- I graph and telephone branches greatlyreduced or'entirely' eliminated. In Fig. '3 the telegraph branches T T,are connected to the line circuit atthe points 00 which are midwaybetween the serially connected secondary windings I 1,, and I, Irespectively, of the repeating coil. The primary I of said repeatingcoil, as before, is shunted across the drop side of the composite systembetween the points p p. It will be obvious that the points 0 0 in Fig.3, which are respectively between the outer ends of the two coils ofeach of the two sets of secondaries of the repeating coil, are pointshaving their potential unaflected by the development of varying currentsuch as ringin current .in the primary of said coil, so that thetelegraph instruments are not affected by said'current.

' It will be sc'cn conversely that the telegra h currents im ressed onthe system at t e points 0 an 0d1v1deand lnduce approximately equal andopposite efiects in the primary I -so that the'harmful effects of suchcurrents upon the telephone receiver will be reduced to a minimum orentirely avoided. A suitable adjustment of the condensers 0' c" and o, 0whereby the amplitudes I and hases of the currents'fio'wing in oppositeirections from the points 0 0- may be regulated, will aid inaccomplishing this result. v 4 An extension of the principles shown inFig. 3 is represented in Fig. 4, which shows an arrangement whereby theeflieiency of transmission of the ringing currents is still furtherincreased by connecting the primaries I I, of the re eating coil inseries with the In the system shown in Fig. 5 the condensers'C C, may beemployed as before between the secondaries of the repeating coil and theshunts which include the impedances L L,, but the condensers O O, can beeliminated and the primaries I andI, connected -metallically in series.-'Ihese con densers being-discarded, the addition of a condenser C', asshown, between-the inner terminals of the secondaries assists in theelimination of the'effect of the telegraph currents in the telephoneinstruments and in-- creases the efficiency of the repeating coil..

In Fig. 5 the telegraph branches are connected at points 0 0, betweenwhich there is developed a practically zero difference of potential bythe ringing currents of the telephone system, so that the operation ofthetele phone system will not appreciably affect the telegraph receiver.Conversely, the currents impressed on the system bythe telegraphbranches divide and induce approximately equal and opposite effects inthe primary windings I, I, of the repeating coil so that thetelephonereceivers will'not be injuriously affected by said currents.This may be accomplished by suitable adjustment of the condensersC and Cor the coils L L or by-the adjustment of both sets of coils andcondensers. It will be obvious to those skilled in the art that a simplerepeating coil, or one having a plurality of secondaries, or a pluralityof primaries and a plurality of secondaries, may be employed in variousways to associate the telephone branch of a composite signaling systemwith the line circuit, and therefore I desire it tovbe understood thatalthough I- have described in detail several arrangements whereby theobjects-of the present invention may be effected, I do not wish to limitmyself to the said specific arrangements, inasmuch as they have beenselected from a number of equivalent systems merely for the purpose ofmore fully disclosing the presentinvention.

I claim:

- 1.. In a composite signaling system, a line circuit, a telegraphbranch, a telephone branch, a repeating coil having all of itssecondaries connected in series with each'other nection from the toegraph branch to the line branch with said line circuit, said repeatingI primary of said repeating coil across the teleand with the two sidesof the linecircuit, a connection from the primary of said repeating coilto said tele hone branch, and .a concircuit through one of saidsecondaries.

2. In a com osite signaling system, a line circuit, two to egraphbranches, a telephone branch, a repeating coil having all of itssecondaries connected in series with each other and with the two sidesof the linercircuit, a connection from the primary of said repeatingcoil to said telephone branch, and connections from the telegraphbranches to the two sides of the line circuit through said secondariesrespectively.

3. In a composite signaling system, a line circuit, a telegraph branch,a telephone branch, a repeating coil operatively associating saidtelephone branch with said line circuit, said repeating coil having aplurality of secondaries in series with each other and with the linecircuit, and a connection from said telegraph branch to the :linecircuit throu b one of said secondaries. I

4. n acom osite si naling system, a line circuit, two teegraph ranches,a telephone branch, a repeating coil operatively associating saidtelephone branch with said line circuit, said repeating coil having aplurality of secondaries in series with each other and. with the linecircuit, and connections from the telegraph branches to the two sides ofthe line circuit through said secondaries respectively.

5. In a composite signaling system, a'li'ne circuit, a composite setincluding a telegraph branch and a telephone branch, are eating coiloperatively associating said to ephone coil having a plurality ofsecondaries in series-1- with each other and with the'line circuit, acbnnection I from said telegraph branch to the line circuit through oneof said seconiilaries and connections bridging the phone side of saidcomposite set.

6. In a composite signaling system, a line circuit, a telegraph branch,a telephone graph branch to the line circuit at a oint having itspotential unaliected by the evel- 8. In a composite si naling system, aline circuit, a telegraph ranch, a telephone branch, a repeating coilhaving two second-' aries connected 111 series w1th each other and withone of the sides of the line circuit, 'a connection from said telegraphbranch to a point between the outer ends of said secondaries, a lated tosai from said telephone branch to said primary winding.

9. In a composite si naling system, a line circuit, a telegraph ranch, atelephone primarywindi'ng inductively resecondaries, and'a connectionbranch, a repeating coil having two sets of secondaries each setconsisting of two-coils connected in series with each other and with oneof the sides of the line circuit,'a connection from saidtelegraph branchto a point between the outer ends of the twocoils of one of said sets-ofsecondaries, a primary winding inductively related to saidsecondariesand a connection from said telephone branch to said primarywinding.

10. In a composite signaling system, a line circuit, two telegraphbranches, a-telephone branch, a repeating coil having two sets ofsecondaries, each set consisting of two coils connected in series witheach other and with one of the sides of the line circuit, connec- .tionsfrom said telegraph branches to points between the outer ends of the twocoils of each of said sets of secondaries, a primary winding inductivelyrelated tosaid secondaries and a connection from said telephonebranch tosaid primary winding.

In testimony whereof, I have hereunto subscribed HENRY B. STONE.Witnesses:

FREDERICK F. MANcnEsT -R, WILLIAM G. KENDALL.

my name this 16th day of July

